Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
If incorrect collating occurs in a direction of a plurality of documents when the documents are set on an automatic document feeder (an ADF) for continuous scanning, copying the documents without correction and automatically executing a bookbinding process cause a big problem. Against such problem, for example, there has been proposed the following technique. The technique recognizes characters in several kinds of character regions in documents in respective directions of 0 degrees, 90 degrees, 180 degrees, and 270 degrees. The technique determines a direction with the highest degree of confidence (a degree of approximation between the read character and the recognized character) among degrees of confidence of the character recognition in the respective directions as a document direction. Meanwhile, a technique that makes a process to determine a direction of images efficient has also been proposed. This technique, specifically, recognizes characters in one direction based on a direction of documents up to the previous page or the most frequent direction of the documents from the first page to the previous page to determine the direction of the documents of the second page and after the second page. When an approximate value (closeness of a feature of a vector by collation with vector information of each character) as a result of the character recognition is equal to or more than a threshold, the technique determines that the direction of the documents matches. Note that, when the approximate value is less than the threshold, the technique recognizes the characters also in another direction and determines a direction in which the highest reliable recognition result is obtained as the direction of the documents.